Localization of a Novel Ryanodine Receptor Gene (RYR3) to Human Chromosome 15q14-q15 by in Situ Hybridization

Ryanodine receptors (RyRs) are intracellular Ca[sup 2+] release channels responsible for the release of Ca[sup 2+] from intracellular stores following transduction of many different extracellular stimuli. The genes of the two RyRs, originally described in the sarcoplasmic reticulum of skeletal (RYR1) or cardiac (RYR2) muscles, have been cloned and mapped on chromosome 19q13.1 and chromosome 1, respectively, in humans. The RYR1 gene has been shown to be tightly linked to the locus for malignant hyperthermia susceptibility (MHS). A single-point mutation in RYR1 has been identified as the possible cause of MHS in swine and of at least some forms of MHS in human. Another MHS locus has been mapped on human chromosome 17q11-q24. We have recently cloned a third RyR (RYR3) from mink, which appears to be widely expressed. A RyR with 94% homology to mink cDNA has also been isolated from rabbit brain.